The overall goal of the Research Resource Multiscale Modeling Tools for Structural Biology is the development and integration of modeling tools for the exploration of multi-resolution models in structural biology. Problems in structural biology require researchers to move between models of low-resolution and detailed atomic models, to fully explore and exploit experimental information. Our resource efforts, through core and collaborative research programs, are focused on the development of new and integrated approaches to multiscale modeling in four primary focus areas: [unreadable] -Modeling of large-scale assemblies of nucleic acids and proteins with nucleic acids, including the facile transitioning between models at full atomic resolution and low-resolution representations. [unreadable] -Protein structure prediction and refinement using hybrid methods, combining lattice-based Monte Carlo algorithms with force field based methods, including the requisite tools. Computational infrastructure and data bases that facilitate the development of prediction pipelines. [unreadable] -The development of algorithms, methods and tools to explore large-scale motions that occur during a virus life cycle; i.e., assembly, maturation and infectivity, as well as a web-based infrastructure and data repository for virus structures and derived properties. [unreadable] -Novel methods and tools to be used by structural biologists employing cryo-EM to build and refine multiscale structural models. Particular focus will be given to the flexible refinement of atomic-level structures into low-resolution data using elastic network normal mode methods. [unreadable] [unreadable] An additional core research effort ties these threads together, through the development and distribution of computer codes, to make such simulations readily accessible to the scientific community at large. We complement these developments by: [unreadable] -Collaborations that challenge and direct our Core research efforts [unreadable] -Dissemination and distribution of algorithmic and methodological developments, through the established distribution mechanisms employed for the widely distributed AMBER and CHARMM molecular modeling packages [unreadable] -Continued development of the VIPER "web-base" for structural virology [unreadable] -Training of biomedical researchers through research and training workshops [unreadable] [unreadable]